Location: Healthy Processed Foods ResearchTitle: Effect of isochoric freezing on quality aspects of minimally processed potatoes
|ZHAO, YUANHENG - Engineering Design|
|Wood, Delilah - De|
|POWELL-PALM, MATTHEW - Engineering Design|
|RUBINSKY, BORIS - Engineering Design|
Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/27/2020
Publication Date: 8/28/2020
Citation: Bilbao-Sainz, C., Zhao, Y., Takeoka, G.R., Williams, T.G., Wood, D.F., Chiou, B., Powell-Palm, M., Wu, V.C., Rubinsky, B., McHugh, T.H. 2020. Effect of isochoric freezing on quality aspects of minimally processed potatoes. Journal of Food Science. 85(9):2656-2664. https://doi.org/10.1111/1750-3841.15377.
Interpretive Summary: Minimally processed potato products can save time to consumers and the catering industry. However, the shelf life of minimally processed potato products is limited. Freezing and frozen storage can be used for the long term preservation of cut potato products. However, the ice crystals developed during freezing may cause cell damage resulting in lower product quality after thawing. A new technique called isochoric (constant volume) freezing preserves biological matter at subfreezing temperatures without any ice damage. We examined the effects of isochoric freezing on the physical and nutritional properties of peeled and diced potato cubes and compared the results with IQF currently used in the food industry. We found that isochoric freezing led to improved quality stability of pre-cut potato cubes when compared with IQF. Isochoric freezing resulted in thawed potatoes with lower drip loss and volume shrinkage as well as better texture properties compared with IQF. Isochoric freezing and IQF did not prevent browning of fresh potato, although the isochoric sample showed some delay in browning.
Technical Abstract: The enhanced interest in greater convenience foods has recently led to the expansion of minimally processed potato products. This study investigated the effects of isochoric freezing on pre-peeled potato cubes, including quality attributes (microstructure, texture and color), nutritional value (ascorbic acid content, total phenolic content and antioxidant capacity) and polyphenol oxidase activity. Isochoric freezing (-3°C/30 MPa) was compared with isobaric freezing (-3°C/0.1 MPa) and individual quick freezing (IQF) followed by frozen storage at -20°C for four weeks. The isochoric sample had lower drip loss and volume shrinkage as well as better preserved texture and microstructure than the other samples. All freezing methods caused an increase in total phenolic content and antioxidant capacity, but a decrease in ascorbic acid content. Also, all freezing methods caused browning of the thawed potatoes, but isochoric freezing delayed their onset for the longest time.